Precision boring machine

ABSTRACT

A precision boring machine with compensated thermal deformation comprising a bed, one or two frames carrying, each, at least one spindle head and secured on the bed, and a work table for mounting the workpieces, said table sliding along the bed during boring operations, to compensate for the thermal deformations of the frame and spindle head and to improve the precision of machining, each spindle head is secured on the frame surface facing the work table so that it is located between the frame, and the work table.

Elite Sttes atet 1 3,692,418 Kopelev [451 Sept, 19, 1972 [54] RECISIONBORENG MACHINE FOREIGN PATENTS OR APPLICATIONS [72} Inventor: FridrikhLvovich Kopelev, Kom- 531,783 1/1941 Great Britain ..408/234 somolskayaulitsa, 43, kv. 5, Odessa,

U S, R Primary Examiner--Francis S. Husar Filed: g 1970 AttorneyI-lolman& Stern 21 Appl. No.: 67,733 1 ABSTRACT A precision boring machine withcompensated ther- 52 us. Cl. ..408/8, 408/37, 408/234, demmafi mprisinga frames carrying, each, at least one spindle head and secured 82/DIG' 1on the bed, and a work table for mounting the work- [51] Int. Cl ..B23b39/22, B23b 47/00 pieces, Said table sliding along the bed during boring[58] Field Of Search ..408/8, 37, 39, 56, 234; operations, to compensatefor the thema] dgforma- 82/900 tions of the frame and spindle head andto improve the precision of machining, each spindle head is [56]References Cited secured on the frame surface facing the work table sothat it is located between the frame, and the work ta- UNITED STATESPATENTS ble.

3 ,5 84,524 6/1971 Langenbach ..408/56 1 1 Claims, 5 Drawing FiguresPATENTED 19 I973 3.692.418

SHEET 1 0F 2 Fi .2 FIG! Fig.5

Iuvmwvrug, $5.4M {MW b edar;

PATENTED EP 19 7 3.692 418 SHEET 2 or 2 IuvawrvA. 5 ZW-MLA, M 57 M 4A123.

PRECISION BORING MACHINE The present invention relates to precisionboring machines and can be used, for example, in the machine utilizingdiamond and carbide tools for the precision machining of articles. Knownin the art are precision boring machines comprising a bed, one or twoframes carrying one or more spindle heads with spindles. The frames aresecured on the bed while the workpiece is set on the table which slidesalong the bed in the course of boring. The machines are equipped withspecial devices aimed to reduce and compensate for the thermaldeformations, said devices being made in the form of cooling units.

The main disadvantage of the known machines lies in the complex designand installation of cooling units. Besides, in these machines thethermal deformations of the spindle shaft and of the frame carrying thespindle heads are directed towards one and the same side and are summedup, reducing the precision of boring.

An object of the invention is to alter the layout of the units of theprecision boring machine.

This object is accomplished by providing a precision boring machine withcompensated thermal deformations, said machine comprising a bed, one ortwo arched frames carrying, each, at least one spindle and mounted onthe bed, and a work table for mounting the workpieces movable along thebed in the course of boring in which, according to the invention eachspindle head is secured on the frame surface facing the work table sothat said head is located between the frame and the work table.

A machine in which the frame pillars are hollow and pillars with aliquid may have transmitters registering the displacement of the spindleshaft and located, each, on the spindle head, and other transmittersregistering the displacement of the frame caused by thermal deformationsand located in the hollow frame pillars, these pillars alsoaccommodating heater elements which are energized by the signals sent bysaid transmitters to compensate for the displacement of the spindleshaft in a required direction.

It is practicable that the function of transmitters registering thedisplacement of the spindle axis be performed by temperaturetransmitters.

Other objects and advantages of the present invention will be describedhereinbelow by way of example with reference to the accompanyingdrawings, in which:

FIG. 1 is an end elevational view of the precision boring machineaccording to the invention,

FIG. 2 shows an end elevational view of another embodiment of theprecision boring machine incorporating two spindle heads according tothe invention,

FIG. 3 shows a side elevational view of the two-frame precision boringmachine according to the invention, with portions in section,

FIG. 4 shows a fragmentary section of FIG. 1 taken along the framepillars,

FIG. 5 is a diagram of a heater circuit connections according to theinvention.

The precision boring machine comprises a bed 1 (FIG. I), an arched frame2 secured on the bed I and a spindle head 3, which is fastened not onthe upper surface 4 of the frame as it is done in the known machines,but on its lower surface 5 facing the work table 6. Such a layoutautomatically compensates within certain limits for the thermaldeformations of the machine, since the thermal expansions of the body ofthe spindle head 3 and of the pillars of the frame 2 causedifferently-directed displacement of the shaft of the spindle 7, beingsubtracted from each other whereas in the ordinary layout thesedisplacements are added, thereby impairing the precision of the machine.

FIG. 2 shows another embodiment of the machine comprising a secondspindle head 8 located, like the spindle head 3, on the lower surface 5of the frame 2.

FIG. 3 shows a two-frame machine which comprises a second frame 9 with aspindle head 11 secured on its lower surface 10.

Partial compensation of thermal deformation is achieved in equal degreein these embodiments of the claimed disclosed machines.

In all cases the upper surface 4 of the frame 2 is free for theinstallation of the drive motors 12 whose heating in operation has apositive function, causing additional thermal displacements.

In some cases the claimed layout offers additional advantages when, forexample, the requirements of precision call for ensuring a minimumdistance from the shaft of the spindle 7 to the guides of the table 6,also when installing widely-used attachments 13 with top-located set-upbases 14 for holding the workpiece 15 as shown in FIG. 3.

An advantage of these devices lies in reliable protection of the set-upbases 14 against the action of chips which becomes particularlyimportant in automated loading.

It is preferable that the upper part of the frame be made separatelyfrom the pillars for facilitating machining and finishing the surfacefor mounting the spindle head. Depending on the adopted method formachining of the bed guides, the pillars may be either cast integralwith the bed or be separate as shown in FIG. 4.

For additional precision, the degree of compensation for thermaldeformation of the shaft of the spindle 7 is increased'by the use of adevice shown in FIG. 4. The pillars 16 of the frame 2 are made hollowand their spaces are filled with a liquid, e.g. a mineral oil. The bodyof the spindle head 3 accommodates a temperature transmitter 17, forexample a resistance thermometer which can be substituted by any otherpick-up responding to the displacement of the spindle shaft.

Located inside the pillars 16 of the frame 2 are the transmittersregistering the displacement of the frame due to thermal deformation forexample, temperature transmitters 18, and heater elements 19.

An elementary diagram of circuit connections of the transmitters 17 and18 and heater elements 19 is shown in FIG. 5. The temperaturetransmitters l7 and 18 of the spindle head and frame are electricallyconnected with the temperature transmitters 20 and 21 of the ambientmedium forming a bridge circuit which is connected to the mains througha converter 22 and a switch 23. The bridge circuit comprises adjustingresistors 24 and 25.

Cut into another diagonal of the bridge circuit is an adjustingpotentiometer 26 with a relay 27 connected to its output.

The heater elements 19 are connected to a secondary winding 29 of thetransformer 30 through contacts 27 of the relay 27 and an adjustingresistor 28.

Additional heating of the frame pillars is effected as follows.

The supply circuit of the heater elements is fed via the startercontacts 31 (starter not shown), the supply voltage being stepped downby the transformer 30.

The bridge circuit is supplied from the main through the converter 22.

While adjusting the machine, a required relation is set between thespindle temperature at 3 and that of the pillars 16 of the frame 2 toensure the largest possible degree of compensation for thermaldeformations. The temperature of the spindle head should beapproximately three times higher than the temperature of the posts.

The required relation of temperatures is obtained with the aid of theadjusting resistors 24 and 25 cut into the circuit. A condenser 32smoothes out the voltage pulsations The machine and ambient temperaturesbeing equal, the bridge circuit is in balance. When the spindle head 3gets heated in operation, and there appears an out-ofbalance voltage inthe diagonal of the bridge circuit; this voltage is fed to the input ofthe adjusting potentiometer 26 which switches on the heater elements 19in the pillars 16 of the frame 2 through the contacts 27 of the relay27. As a preset, temperature difference is attained, the out-of-balancevoltage drops and the heater elements 19 cut off. The sensitivity of thecircuit ensures the maintenance of the required relation between thetemperatures of the head 3 and frame 2 within the entire period ofwarming and operation of the machine.

I claim:

1. A precision boring machine comprising a bed; a frame secured on saidbed; a work table for fastening the workpieces sliding along said bedduring boring operations; at least one spindle head with the spindlerigidly secured on the plane of said frame and facing said table so thatsaid head, without moving relative to the machines immovable parts isconstantly arranged between said frame and the work table, said spindlehead being fastened on the frame surface facing said work table so thatsaid spindle head is located between said frame and work table; andmeans incorporated in said frame for compensating for the thermaldeformations of said frame, due to operation of said spindle, andthermal deformations of said spindle head whereby the spindle ismaintained substantially true to an adjusted position in spite ofoperational heat of the machine.

2. A precision boring machine comprising a bed; two frames secured onsaid bed; a work table for fastening the workpieces sliding along saidframe during boring operations; two spindle heads with spindles rigidlysecured on the plane of a corresponding frame, facing said work table sothat both said spindle heads, without moving with regard to the machinesimmovable parts, are constantly positioned between said frames and thework table, secured, each, on the surface of the corresponding frame,said surface facing the work table so that both spindle heads arelocated between said frame and work table; means compensating for thethermal deformations of the machine.

3. A precision boring machine comprising a bed; a frame secured on saidbed; a work table for fastening the workpieces sliding along said bedduring boring operations; at least one spindle head with the spindle,fastened on the frame surface facing said work table so that saidspindle head is located between said frame and work table; meanscompensating for the thermal deformations of the machine, comprisinghollow supporting pillars of said frame; liquid filling said framepillars; transmitters registering the displacement of the shaft of saidspindle of the spindle head and located on each of said spindle heads;transmitters registering the displacement of said frame due to thermaldeformations and located in the spaces of said frame pillars; heatingmeans located in said spaces of said frame pillars, connected with saidtransmitters registering the displacement of the spindle shaft andframe; said heating means are energized by the signals sent by saidtransmitters and, heating said liquid, create additional thermaldeformations of the machine which compensate for the displacement of theshaft of said spindle in a required direction.

4. A precision boring machine comprising a bed; two frames secured onsaid bed; a work table for fastening the workpieces sliding along saidframe during boring operations; two spindle heads with spindles,secured, each, on the surface of the corresponding frame, said surfacefacing the work table so that both spindle heads are located betweensaid frame and work table; means compensating for the thermaldeformations of the machine, comprising hollow pillars of said frames;liquid filling said pillars; transmitters registering the displacementof the shaft of said spindles of spindle heads and located on each ofsaid spindle heads; transmitters registering the displacement of saidframes due to thermal deformations and located in said spaces of hollowframe pillars; heating means located in said spaces of frame pillars andconnected with said transmitters registering the displacement of thespindle shaft and frame; said heating devices are energized by thesignals sent from said transmitters and, heating said liquid, createadditional thermal deformations of the machine which compensate for thedisplacement of the shaft of said spindle.

5. A machine according to claim 3 wherein the function of thetransmitters registering the displacement of the spindle shaft isperformed by temperature transmitters.

6. A machine according to claim 4 wherein the function of thetransmitters registering the displacement of the spindle shaft isperformed by temperature transmitters.

7. A precision boring apparatus comprising:

a bed;

a frame projecting vertically above said bed;

said bed including a work table thereon for mounting a work piece formovement toward and away from said frame in the plane of said bed duringboring operations; a spindle head suspended from the under surface ofsaid frame in spaced, overlying relation to said work table; saidspindle head including a spindle projecting from said spindle head inparallel relation to the plane of said work table for engagement withthe work piece;

said frame comprising an arched member straddling and including pillarsdepending on each side and spaced from said spindle head whereby heatgenerated and transmitted from said spindle is not directly transmittedto said pillars,

whereby thermal deformations are substantially eliminated at saidspindle head, said frame and spindle substantially eliminating theremaldeformation of said spindle relative to the work table.

8. The apparatus as claimed in claim 7 in which said pillars includemeans automatically sensing and compensating for thermal deformation ofsaid spindle head and spindle relative to the work table.

9. The apparatus as claimed in claim 8 in which said means automaticallycompensating for thermal deformation comprises heat-transmitter meansand heating means intimate with said pillars whereby deformation due tooperational heat is substantially negated due to compensation by saidmeans automatically sensing and compensating for thermal deformation.

10. The apparatus as set forth in claim 9 in which said pillars includea fluid therein and heat transmitters operatively connected to saidspindle head and said pillars, said heating means being operativelyconnected to said fluid and a thermal compensating circuit wherebythermal deformations at the spindle are substantially negative when theapparatus is in operation.

11. The apparatus as claimed in claim 7 including power means mounted onthe upper surface of said frame in opposition to said spindle headwhereby thermal expansion caused by heat generated by operation of saidspindle and said power means substantially cancel each other out.

1. A precision boring machine comprising a bed; a frame secured on saidbed; a work table for fastening the workpieces sliding along said bedduring boring operations; at least one spindle head with the spindlerigidly secured on the plane of said frame and facing said table so thatsaid head, without moving relative to the machine''s movable parts isconstantly arranged between said frame and the work table, said spindlehead being fastened on the frame surface facing said work table so thatsaid spindle head is located between said frame and work table; andmeans incorporated in said frame for compensating for the thermaldeformations of said frame, due to operation of said spindle, andthermal deformations of said spindle head whereby the spindle ismaintained substantially true to an adjusted position in spite ofoperational heat of the machine.
 2. A precision boring machinecomprising a bed; two frames secured on said bed; a work table forfastening the workpieces sliding along said frame during boringoperations; two spindle heads with spindles rigidly secured on the planeof a corresponding frame, facing said work table so that both saidspindle heads, without moving with regard to the machine''s immovableparts, are constantly positioned between said frames and the work table,secured, each, on the surface of the corresponding frame, said surfacefacing the work table so that both spindle heads are located betweensaid frame and work table; means compensating for the thermaldeformations of the machine.
 3. A precision boring machine comprising abed; a frame secured on said bed; a work table for fastening theworkpieces sliding along said bed during boring operations; at least onespindle head with the spindle, fastened on the frame surface facing saidwork table so that said spindle head is located between said frame andwork table; means compensating for the thermal deformations of themachine, comprising hollow supporting pillars of said frame; liquidfilling said frame pillars; transmitters registering the displacement ofthe shaft of said spindle of the spindle head and located on each ofsaid spindle heads; transmitters registering the displacement of saidframe due to thermal deformations and located in the spaces of saidframe pillars; heating means located in said spaces of said framepillars, connected with said transmitters registering the displacementof the spindle shaft and frame; said heating means are energized by thesignals sent by said transmitters and, heating said liquid, createadditional thermal deformations of the machine which compensate for thedisplacement of the shaft of said spindle in a required direction.
 4. Aprecision boring machine comprising a bed; two frames secured on saidbed; a work table for fastening the workpieces sliding along said frameduring boring operations; two spindle heads with spindles, secured,each, on the surface of the corresponding frame, said surface facing thework table so that both spindle heads are located between said frame andwork table; meanS compensating for the thermal deformations of themachine, comprising hollow pillars of said frames; liquid filling saidpillars; transmitters registering the displacement of the shaft of saidspindles of spindle heads and located on each of said spindle heads;transmitters registering the displacement of said frames due to thermaldeformations and located in said spaces of hollow frame pillars; heatingmeans located in said spaces of frame pillars and connected with saidtransmitters registering the displacement of the spindle shaft andframe; said heating devices are energized by the signals sent from saidtransmitters and, heating said liquid, create additional thermaldeformations of the machine which compensate for the displacement of theshaft of said spindle.
 5. A machine according to claim 3 wherein thefunction of the transmitters registering the displacement of the spindleshaft is performed by temperature transmitters.
 6. A machine accordingto claim 4 wherein the function of the transmitters registering thedisplacement of the spindle shaft is performed by temperaturetransmitters.
 7. A precision boring apparatus comprising: a bed; a frameprojecting vertically above said bed; said bed including a work tablethereon for mounting a work piece for movement toward and away from saidframe in the plane of said bed during boring operations; a spindle headsuspended from the under surface of said frame in spaced, overlyingrelation to said work table; said spindle head including a spindleprojecting from said spindle head in parallel relation to the plane ofsaid work table for engagement with the work piece; said framecomprising an arched member straddling and including pillars dependingon each side and spaced from said spindle head whereby heat generatedand transmitted from said spindle is not directly transmitted to saidpillars, whereby thermal deformations are substantially eliminated atsaid spindle head, said frame and spindle substantially eliminatingtheremal deformation of said spindle relative to the work table.
 8. Theapparatus as claimed in claim 7 in which said pillars include meansautomatically sensing and compensating for thermal deformation of saidspindle head and spindle relative to the work table.
 9. The apparatus asclaimed in claim 8 in which said means automatically compensating forthermal deformation comprises heat-transmitter means and heating meansintimate with said pillars whereby deformation due to operational heatis substantially negated due to compensation by said means automaticallysensing and compensating for thermal deformation.
 10. The apparatus asset forth in claim 9 in which said pillars include a fluid therein andheat transmitters operatively connected to said spindle head and saidpillars, said heating means being operatively connected to said fluidand a thermal compensating circuit whereby thermal deformations at thespindle are substantially negative when the apparatus is in operation.11. The apparatus as claimed in claim 7 including power means mounted onthe upper surface of said frame in opposition to said spindle headwhereby thermal expansion caused by heat generated by operation of saidspindle and said power means substantially cancel each other out.